Graphene Silly Putty detects pitter-patter of spider footsteps

SILLY SENSOR Scientists created a pressure sensor by mixing graphene into polysilicone, a stretchy, viscous goo, forming a gray putty, as shown by study coauthor Jonathan Coleman of Trinity College Dublin. Polysilicone is also found in the children’s toy Silly Putty, shown by Coleman’s son Oisin.

Graphene-infused Silly Putty forms an electrical sensor that is sensitive enough to detect the gentle caresses of spider feet walking across it.

Mixing graphene, or atom-thick sheets of carbon, and polysilicone, the substance found in the children’s toy Silly Putty, made it conduct electricity. Its electrical resistance was highly sensitive to pressure: Squishing the putty caused the graphene sheets within to shift and disconnect, impeding the flow of electricity.

When placed on a person’s neck over the carotid artery, the putty could monitor pulse and blood pressure via changes in the material’s resistance. The putty could also detect breathing and finger motions. To illustrate just how sensitive the sensor was, scientists coaxed a small spider to walk over the putty; the sensor registered the spider’s footfalls, researchers report December 9 in Science.